The present invention relates to methods of sealing an injection site, where therapeutic agent has been injected into tissue resulting in increased efficiency or agent uptake. The present invention also relates to methods for delivering therapeutic agent to a tissue, which include injecting a therapeutic agent into a tissue and subsequently sealing the injection site, or engaging an injection device with the tissue for a sufficient period of time that sealing is not necessary to avoid leakage of the therapeutic agent.
The treatment of disease such as vascular disease by local pharmacotherapy presents a means of delivering therapeutic drug doses to target tissues while minimizing systemic side effects. Such localized delivery of therapeutic agents has been proposed or achieved using medical devices such as catheters, needle devices and various coated implantable devices such as stents.
The localized delivery of therapeutic agents using needle devices has the advantages of precise placement and accurate control over the volume and rate of delivery. The processing mechanisms by which therapeutic agent is released from the needle and absorbed by surrounding tissue, however, is not well-characterized.
In one embodiment, the invention includes a method of sealing an injection site by performing radio frequency cautery at the mouth of a needle track in tissue in order to seal the mouth of the needle track. The needle track is formed in tissue after a therapeutic agent has been injected into a tissue with an injection device and subsequently removed from the tissue.
In other embodiments the mouth of a needle track in tissue is sealed by performing resistance heating at the mouth, performing laser heating at the mouth, plugging the mouth with a solid plug, and coagulating material at the mouth of the needle track.
In another embodiment, the invention includes a method of delivering therapeutic agent to tissue by injecting the therapeutic agent into the tissue of a mammal with an injection device, where the injection device is kept engaged with the tissue for a sufficient period of time after the injection has been completed to prevent the therapeutic agent from leaking from the injection site.
In other embodiments, the invention includes methods of delivering therapeutic agent to tissue, wherein a thickening agent, bioadhesive material or tissue sealant is added to the materials being delivered to reduce or eliminate dispersion or leakage of the therapeutic agent from the tissue after injection into the tissue. The therapeutic agent is delivered by injecting the therapeutic agent into tissue, preferably by an injection needle.
In another embodiment, the invention includes a method for delivering a therapeutic agent into a tissue in a mammal, which includes injecting a therapeutic agent into tissue with an injection needle, withdrawing the injection needle from the tissue, thus forming a needle track having a mouth in the tissue, and sealing the mouth of said needle track. Preferably, the mouth of the needle track is sealed by radio frequency cautery. In other embodiments, the mouth of the needle track is sealed by resistance heating, laser heating, plugging the mouth with a solid plug, or by coagulating a material at the mouth of the needle track.